1. Field of the Invention
This invention relates to the fluid transfer art and more particularly to an improved system for transferring aliquots of a sterile solution from a bulk container to a plurality of other containers.
2. Description of the Prior Art
There have heretofore been proposed several types of devices for withdrawing aliquots from a container of bulk solution. The most common such device includes a conventional syringe for withdrawing aliquots of sterile solution from a stoppered bottle. In such cases, a volume of air is commonly injected into the bottle with the syringe to facilitate withdrawal of the desired aliquot of solution. If no air is injected, a partial vacuum develops within the bottle, making withdrawal of solution therefrom very difficult. However, the introduction of non-sterile air to the bottle may contaminate the solution contained therein and lead to serious medical consequences to a patient receiving the solution.
The problems associated with the withdrawal of liquid from a container of sterile solution are most severe when relatively large quantities of liquid are to be withdrawn on a frequent basis. Such is the case, for example, when hospital pharmacies add aliquots of concentrated aminophylline, KCl or multiple vitamin injection (MVI) to containers of intravenous solution. The concentrated additives are provided in bulk containers from which the desired aliquots must be taken, and the process of transferring aliquots from the bulk containers to different bottles of IV solution is repeated numerous times each day. It is thus of extreme importance in such cases that each transfer be effected with as little contamination as possible of the solution within the bulk container.
Devices have been proposed for venting the interior of a bottle from which quantities of solution are to be removed to allow air to be drawn into the bottle and thus equalize the pressures within and without the bottle. A filter may then be provided for removing unwanted impurities from the air drawn into the bottle. The prior vent structures have generally involved a passage open to the outside air and leading to the interior of the bottle, closed only by a filter element such as a small wad of cotton. Such devices, however, are subject to leakage through the filter element when the bottle is turned upside down for removal of solution therefrom. The problem of leakage is particularly acute where it is desired to hang the bottle upside down for long periods of time to remove successive aliquots therefrom.
Therefore, in many applications it is desirable to provide a vented device for aseptic transfer of aliquots from a container of bulk solution without leaking or spilling any of the solution, regardless of the orientation of the container.